This invention relates to a method of eliminating undesirable deposition from the inside of a reaction chamber for CVD.
Recently, we have proposed a new method for depositing carbon films on substrates by applying a microwave and a magnetic field to a carbon compound gas in a vacuum chamber. The chemical vapor reaction causes necessarily undesirable deposition on the inside of the reaction reaction chamber.
It has been known as a removing technique to subject the carbon film to etching, particularly, to etch an amorphous film by means of Electron Cyclotron Resonance (ECR). In the prior art, active particles such as derived from a fluorine compound gas or chlorine compound gas are produced by ECR at a suffciently low pressure where at least electrons can make respective circular paths, and drifted to a substrate disposed apart form the resonating space by virtue of a divergent magnetic field.
However, in such a prior art, the wear of the apparatus is accelerated because of the use of fluorine compound or chlorine compound as an etchant gas, in particular the exhaustion oil is degraded. For this reason, it is required to remove unnecessary products deposited on the inside of the reaction chamber without making use of a fluorine compound and a chlorine compound to clean the reaction chamber after taking out the substrate coated with a film composed mainly of carbon or its compound(s) from the chamber, so that the inside wall of the reaction chamber is not damaged by errosion.